000
WTNT41 KNHC 112035
TCDAT1
 
TROPICAL STORM PATTY DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162012
500 PM EDT THU OCT 11 2012
 
SATELLITE IMAGES INDICATE THAT WHILE THE CYCLONE REMAINS
SHEARED...CONVECTION IS A LITTLE CLOSER TO THE CENTER THAN EARLIER
TODAY.  SUBJECTIVE DVORAK ESTIMATES FROM TAFB AND SAB ARE 45
KT...WHILE THE CIMSS ADT IS AT 35 KT.  WHILE THE SUBJECTIVE VALUES
LOOK A BIT HIGH...GIVEN THE STEADY CONVECTION TODAY...IT SEEMS
LIKELY THAT THE SYSTEM HAS INTENSIFIED SINCE THE 30-KT ASCAT PASS
FROM LAST NIGHT.  THUS THE INITIAL WIND SPEED IS CONSERVATIVELY SET
TO 35 KT...MAKING PATTY THE SIXTEENTH NAMED STORM OF THE SEASON.  

THE TROPICAL STORM APPEARS TO BE ON BORROWED TIME AS THERE ARE A
COUPLE OF FACTORS COMING TOGETHER THAT SHOULD WEAKEN THE CYCLONE. 
FIRST...SOUTHWESTERLY SHEAR SHOULD INCREASE DURING THE NEXT DAY OR
SO DUE TO A BUILDING LOW-LEVEL RIDGE OVER THE WESTERN ATLANTIC AND
PERSISTENT UPPER-LEVEL SOUTHWESTERLY FLOW.  SECOND...A COLD FRONT
IS LOCATED IN THE WESTERN PORTION OF THE CIRCULATION...AND SOME OF
THAT DRIER AND MORE STABLE AIR WILL LIKELY ENTRAIN INTO THE CENTER. 
THESE ENVIRONMENTAL CONDITIONS SHOULD CAUSE THE CYCLONE TO WEAKEN
BY TOMORROW...AND WILL LIKELY CAUSE PATTY TO SHEAR APART INTO A
TROUGH.  THIS SCENARIO IS IN GOOD AGREEMENT WITH THE GLOBAL MODEL
FORECASTS...AND NO SUBSTANTIAL CHANGE IS MADE TO THE PREVIOUS
FORECAST AFTER ACCOUNTING FOR THE SLIGHTLY HIGHER INITIAL WINDS.  

THE CYCLONE HAS NOT MOVED MUCH TODAY...PROBABLY DUE TO THE CENTER
MAINTAINING VERTICAL COHERENCE IN SPITE OF THE SHEAR.  GLOBAL
MODELS STRONGLY SUGGEST THAT PATTY WILL MOVE TO THE SOUTHWEST BY
TOMORROW AS HIGH PRESSURE BUILDS INTO THE WESTERN ATLANTIC OCEAN. 
THE OFFICIAL FORECAST IS LITTLE SLOWER THAN THE PREVIOUS FORECAST
INITIALLY...THEN IS BLENDED NEAR THE LATEST CONSENSUS AT 24H. 

GIVEN THE STRONG SOUTHWESTERLY UPPER-LEVEL WINDS...IT IS UNLIKELY
THAT PATTY COULD REACH THE BAHAMAS AS A TROPICAL STORM...AND
THEREFORE NO WATCHES OR WARNINGS ARE IN EFFECT FOR THOSE ISLANDS.  
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  11/2100Z 25.8N  72.5W   35 KT  40 MPH
 12H  12/0600Z 25.4N  72.9W   35 KT  40 MPH
 24H  12/1800Z 24.9N  73.4W   30 KT  35 MPH
 36H  13/0600Z...DISSIPATED
 
$$
FORECASTER BLAKE